Drill bit



40 .tion of cutter 6 is a point portion 6c having spiral rotation of'said Cum-,er than the teem of Seid Patented Oct. 1936 i 2,057,026

UNITED STATES PATENT oFFlcE DRILL Brr- George G. Harrington, Houston,Tex., assigner' to Reed Roller Bit Company, Houston, Tex., a.corporationof Texas Application June 11, 1935, seriai No. 26,062

11 claims.` (c1.25571) This invention relates generally to deep well.rotation than the teeth of the former. These drills and specifically toroller bits. l teeth may be straight, as shown.

Some conventional deep well rock bitshave sub- The straight teeth of thecutters 4 and 5 and' vstantially conical cutters rotatable on axes extheteeth of the base portions 6a and 6b of the 5 tending downwardly andinwardly toward the cutter 6 cut away the major portion of the bottom 5longitudinal axis of, the head. The point porof the-hole and the spiralteeth of the point portions of the conventional cutters are small andtion 6c of the cutter 6, driven by the traction of incapable ofeiiciently cutting away the central the straight teeth on said baseportions 6a and 6b portion of the hole, and this results in a most cutsand removes the central portion of the bot- 10 ineiicie'nt operation ofthe drill. tom of the hole, so that the entire area of forma- 10 Thespecific object of this invention is to protion is eiiciently drilled.vide a roller bit having the advantages of the cone The cui-,ting edgesof the teeth on the base porbit but nellldng Cutters COflStrlleted anda1'- tions 6a and 6b of the cutter 6 are shown in 10nranged in a new andimproved marmer t0 e- 'gitudinal alinement with the axis of the cutterCien-T113" Cnt away Said Central DOIOU as Weii as but the angle may besomewhat varied if desired,

the remainder of the bottom of the well. While preserving the driviiigfunetiorr The preferred embodiment 0f the invention in Various otheradvantages of the invention will a three cutter b1t 1s illustrated bythe accompany- `be apparent to those skilled in the art. ing drawingwherein Fig. 1 is a fragmentary ele- I claim: f

vaton of .the bit, and Fig. 2 a bottom plan thereof. 1.l A roller bithaving a head and three roller 20 The bit head i has three dependingbearing cutters mounted on said head, rotatable on axes roiections 2 atabout 120 degrees apart and inclined downwardly and inwardly toward therom each of these a' Conventional bearing indi' lon itudinal xis of saidhead and arran ed to cated by the dotted lines 3, projects downwardly ga g traverse substantially the'entire area of 'the bot- 'ligdmwardiytoward the longitudinal axis of the tom of the hole;"each of saidcutters extending 25 beyond the periphery of the head; two of saidcutters being' substantially frusto-conical, each V .having an innerportion'and an outer portion, the l and are constructed and arranged 1n'a new and teeth on the Outer portion being at a lesser angie improvedmanner which Wiii now be described to the axis of rotation than theteeth on the inner 30 The cutter 6 has a substantially frusto-c0nicalportion; and the other of Said cutters having a base Comprising Outerand inner poiiions 6a and i point portion and a base, said base havinginner 6b, the teeth of the former of whlch are at a and outer portions,said point peri-,ion having lesser angle t0 th aXS 0f IOSZOU Of theCutter spiral Cutting teeth extending upwardly and outthan are the teethof the latter. These teeth are Wardly from a point substantially at the1ongi 35 -preferably of the chisel type beine arranged Subtudinai axisof the head, the teeth on said base stantially in the Same plane Withthe axis 0f being substantiallyv longitudinal to drive said rotation ofthe Cutterpoint portion, the teeth on said inner base por- ExtendingnWaIdly flfOnflV the inner base P01 tion extending at a greater angle tothe axis of The roller cutters 4, 5 and 6 extend inwardly from a pointoutside of the periphery of the head cutting teeth that may be nothed aSShownvpoint portion, and the teeth of said outer base These Spiral teethextend t0 a Point S1110'Sifellileliyl portion extending at a lesserangle to the axis of at the longitudinal aXS 0f the head t0 C1115 androtation of said cutter than the teeth of said inner remove the centerof the bottom of the hole. base portion The desired Speed 0f I'Otatn 0fthe Spiral 13001311 2. A roller bit having a. head and three roller 45point section iS assured by the traction of the cutters 'mounted on saidheadrrotatabie on axes chisel teeth of the base portions 6a and 6b. Thisinclined downwardly and inwardly toward the new and improved combinationeliminates in Y longitudinalaxis of said head, and arranged to actualpractice the problem of eiiiciently removtraverse substantially theentire area of the botinggsaid central portion. tom of thehole; two ofsaid cutters being subo The other roller cutters 4 and 5 aresubstanstantially frusto-conical, each: having an inner tallyfrusto-conical and have outer portions 4a portion and an outer portion,the teeth on the and 5a and inner portions 4b and 5b, the teeth of outerportion being at a lesser angle tothe axis the latter being at a greaterangle to the axis of of rotation than the teeth on the inner portion;

head, the teeth on said base being substantiallyA longitudinal to drivesaid point portion, the teeth on said inner base portion extending at agreater angle to the axis of rotation of said cutter than the teeth ofsaid point portion, and the teeth uf said outer base portion extendingat a lesser angle to the axis of rotation of said cutter thanlthe teethof said inner base portion.

3. A roller bit having a head and three roller cutters mounted on saidhead, rotatable on axes inclined downwardly Iand inwardly toward thelongitudinal axis of said head, and arranged to traverse substantiallythe entire area of the bottom of the hole; two of said cuttersbeing-substantially frusto-conical, and the other of said cutters' asubstantially frusto-conical base, said 'point' portion having spiralcutting teeth extending upwardly and outwardly from a pointsubstantially at the longitudinal axis of the head, the teeth on l saidbase being substantially longitudinal to drive said point portion.

5. A roller bit having a head and roller cutters mounted on'saidvhead,and arranged to traverse vsubstantially the entire yarea of the bottomof the hole; one of said cutters being rotatable on an axis extendinginwardly and downwardly substantially toward the longitudinal axis ofsaid head/and Ahaving a point portion and a base, said point portionhaving spiral cutting teeth extending upwardlyand outwardly from a pointsubstantially at the longitudinal axis of the head, th teeth on saidbase being substantially longitudinal to drive said point portion.

6. A roller bit including a head,.and roller cutters mounted on saidhead and arranged to traverse an area substantially equal to thetransverse area of said head; one of said cutters having the baseportion.

a substantially frustoconical base portion and a point portion extendinginwardly from said' base portion, said base portion having longitudinalteeth and said point portion having spiral teeth,

extending outwardly from a point substantially d at the longitudinalaxis of said head.

7. A roller cutter having a point portion and a substantiallyfrusto-conical base portion, said point portion having spiral-teeth andsaid -base portion havinglongitudinal teeth.

8. A bit having a head and a roller cutter mounted to extend from theperiphery of said inclinedJ downwardlyand inwardly toward thelongitudinal axis of said head, and arranged to traverse substantiallytheentire area of the bottom of the hole, two of said cutters beingsubstantially frusto conical, and the other of said cutters having apoint portion and a base, said point portion having spiral cutting teethextending upwardly and outwardly from a point substantially at thelongitudinal axis of the head, the

' teeth of said base being substantially longitudinal to drive saidvpoint portion, and the teeth on they inner portion of said baseextending at a greater angle to the axis of rotation of said cutter thanthe teeth on said point portion. v

10. A roller cutter having a point portion and .a substantiallyfrusto-conical base portion, said point portion being of smallerdiameter than said base portion, and having spiral teeth, and said baseportion having longitudinal teeth.

11. A roller bit including a head and roller cutters mounted on saidvhead and arranged to traverse an area substantially equal to thevtransverse area of saidhead, one of said cutters having a base portionand a point portion extending from said base portion substantially tothe longitudinal axis of said head, said point portion having spiralcutting teeth, and said base portion having teeth the cutting edges ofwhich extend at a much smaller angle to the axis of the cutter vthan thepitch angle of the s piral cutting teeth on the point portion, wherebythebase teeth will grip the formation more iirmly than the teeth' on thepoint portion; and the teeth on the point portion, will therefore bedriven by the teeth on GaoRcrEl G. HARR'INoToN.

